<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>13-字符串-trim</title>
</head>
<body>
    <script>
        // trim() : 一个字符串的两端删除空白字符，它返回的是一个新的字符串

        var str = '  12 34  ';
        console.log(str.length);  // 9
        console.log(str.trim());  //12 34
        console.log(str.trim().length);  //5
    </script>
</body>
</html>